The impossible password itunes problem

So I've had this ipod for almost a year and it's always worked fine until yesterday. I was on the facebook app and it stalled so I turned it off and when it restarted a picture of a usb and the itunes logo came up. My ipod will not allow me to get past this screen even to enter my password. So here's my problem I tried to connect to itunes and itunes gives me an error message saying it won't even recognize my ipod until I enter my password. I can't enter my password with connecting to itunes and can't connect to itunes without entering my password. I've tried pushing every button on the ipod and I can get to the apple logo but then the same usb/itunes thing comes back up. Does have any ideas how I can fix this?